It looks to me like an blank kit anodised aluminium chassis of the type often found from HK or China based sellers on Ebay. I am currently using a slightly larger one for a project that I am working on.

@blackdod - I like the look that you have achieved. The extra metalwork is a nice touch

Wavebourn...why so many of us have cats?
Now,really....I realised that long time ago......I also see cats on many homes where the music play on audio sistems.
I have 2 tigers and allways came close to the tubes when they are ON.